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B Question about CERN

  1. Aug 11, 2016 #1
    Why haven't the seen supersymmetry or mini black holes at the LHC yet even though it has been running at full power for some time?

    They said these mini back holes were probably happening all the time in out atmosphere so why have they seen none at Cern?

    Do they need a more powerful collider? do black holes and supersymmetry not exist?
     
  2. jcsd
  3. Aug 11, 2016 #2

    Vanadium 50

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    Reference, please.
     
  4. Aug 11, 2016 #3

    mfb

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    Because there are no supersymmetric particles or black holes light enough to be seen with the current dataset.
    The LHC is not running at its full design energy yet, by the way, collisions happen at 13 TeV instead of 14 TeV. And the LHC is expected to collect 100 times more data than collected today, so there is a lot of room left for new discoveries.
    Only in bad pop-science description.


    Our current best model of particle physics is called Standard Model (SM). It does not include supersymmetry, and it does not have black holes. We know the SM is not complete, because it does not describe gravity and because it has some other more subtle issues. Therefore, multiple extensions of the SM have been developed. Some but not all of them include supersymmetry, with different options for their particle masses, a few of them include the possibility to produce black holes. All those extensions are speculative, they don't have to be true, and even if they are their additional particles / black holes could require energies beyond the reach of the LHC.
    We don't know.
     
  5. Aug 11, 2016 #4

    Orodruin

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    No, even without the reference V50 asked you for, you or the person who wrote what you read has misinterpreted the statement. The statement usually made in response to the possibility of creating a mini black hole is that reactions in the atmosphere are very similar to the reactions occurring at the LHC, but in a less controlled manner. Since no doomsday event has occurred due to the atmospheric interactions, it is not to be expected that the LHC will produce such an event. It is not saying that mini black holes are constantly popping up in the atmosphere (how would we know?), it is saying that if they did and if they were catastrophic in nature, we would have known (or rather, not known, since we would not be here to discuss the issue).
     
  6. Aug 11, 2016 #5

    ZapperZ

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    First of all, since you're "new" here, there's one thing you need to know about how this forum is run. Using "They said.." or "I heard that..." is not a sufficient reference source. And yes, we DO require proper reference sources. This is something of an unusual demand, especially if you are used to not having to justify the source of information. But in this forum, the act of forcing people to actually cite their sources inevitably forces them the actually pay attention to not only where they get their information from, but also to make sure that their information is accurate and the source is reputable (i.e. it is not from the National Enquirer).

    This is how a scientific discussion, even in an open public forum such as this, is carried out.

    Secondly, this topic has been discussed at length elsewhere in this forum. If you don't feel like doing a quick search on it, then maybe you might want to read this:

    http://physics.aps.org/articles/v1/14

    And notice, this article gives plenty of references that one can double check to verify its accuracy.

    Zz.
     
  7. Aug 11, 2016 #6

    vanhees71

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    Well the more seriously considered (or conjectured if you wish) possibility of forming mini-black holes is much less spectacular than leading to a cataclysm that destroys the entire universe as we know it. Indeed, there's not the slightest evidence yet that such mini black holes exist at all. One should also note that the possibility of the formation of mini black holes at energy scales of the LHC (of the order of some TeV up to 13 TeV right now) is only given under the assumption of extra dimensions. For a review, see

    https://arxiv.org/abs/1403.0944
     
  8. Aug 11, 2016 #7
    There are many articles online in which scientists suggest the LHC could create mini black holes. I could link them but they probably are a bit hyperbolic.

    This article - https://www.theguardian.com/science/2013/aug/06/higgs-boson-physics-hits-buffers-discovery the scientist do not seem very optimistic about finding evidence of supersymmetry.

    I watched BBC documentary Horizon last night which was about the LHC. One of the main LHC guys on there said that the lHC is now working at full power and another guy there said it could be running for another 20 years, but I just wonder if there's much more to come from it after the discovery of Higgs.

    You can watch the documentary on BBC Iplayer

    http://www.bbc.co.uk/programmes/b07nsxkk
     
  9. Aug 11, 2016 #8

    ohwilleke

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    Building a new collider is inherently a gamble.

    A new collider much more expensive than the LHC (multi-billion dollars) could increase the energy scale probed in controlled experiments by 2-4 orders of magnitude tops. There are 17 or so more orders of magnitude before we hit the theoretically significant Planck scale and there is no real definitive evidence that the Planck scale is actually maximal. If any new physics is outside the energy window between the LHC and the next collider, it was pretty much a waste of money, although we will, of course, get more precise measurements of Standard Model constants and we will keep the knowledge base necessary to build and operate such machines and to analyze their results alive.

    Nobody has any credible estimates of the probability that new physics will appear in that energy window, and we haven't had any strong affirmative hints that there is in fact new physics in that energy window. But, if we want to continue doing new high energy physics in controlled experiments, the only option after the LHC has run its course, it to build a new and bigger collider.
     
  10. Aug 11, 2016 #9
  11. Aug 11, 2016 #10

    ohwilleke

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    Better their tax dollars than mine.
     
  12. Aug 12, 2016 #11

    Orodruin

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    This is still not a valid reference. Saying that many articles exist is not the same as referencing where your statements are taken from.

    The Guardian will generally not be considered a valid scientific reference.

    Again, this is popular science and you must treat it for what it is.
     
  13. Aug 12, 2016 #12
  14. Aug 12, 2016 #13

    ChrisVer

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    Check the discussion after post #14 here:
    https://www.physicsforums.com/threa...data-atlas-nothing-in-spin-0-analysis.881050/

    In general you state it correctly by saying "could", so there is nothing amazing about it...Something that could occure, doesn't necessarily happen. Some theories may predict it, yet so far the experiment has put constraints on those theories.

    First of all studies on the Higgs are still ongoing. Just a discovery of a particle is not the end of it. Higgs is still studied. And there are decay channels which have not reached the stage of "discovery" (for example the Higgs decays to [itex]\tau^+ \tau^-[/itex] or to [itex]b\bar{b}[/itex]).
    Also many other studies are ongoing which concern the Standard Model, some of which are very good [for a hadron collider].

    If by "more" you question about a new particle discovery, nobody knows... if we knew that we would find a particle at 3TeV, someone would have looked for it there. I am not a believer of any type of new physics theory, and I think that's the way to go (at least it saves me from disappointment). Afterall most of the experimental analyses work with the hypothesis that there is nothing new.
     
  15. Aug 12, 2016 #14

    mfb

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    Could. In other words, it is not completely ruled out.
    It is not yet running at the full collision energy, but it is close to that energy since 2015. I don't care what a BBC documentary says: I work with that machine (with one of the detectors to be more precise). ChrisVer and Vanadium 50 work on one of the experiments as well.

    The current plan is to operate the LHC until ~2035, about 20 more years, right.

    There are hundreds of ongoing studies - both searches for new particles and more precise measurement of the known particles. The experiments will produce more precise measurements for at least ~25 more years.
    Don't misrepresent what they say. China is studying a concept for a bigger one. We'll see if it actually gets built, and if the 2020 timescale holds.

    Not just for a hadron collider.
     
  16. Aug 12, 2016 #15

    ChrisVer

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    Maybe the way I typed it gave the wrong impression... For example I know that some parameters have been measured quiet precisely from previous experiments (such as LEP) and similar studies are being done with the LHC, which are of course not as precise but they are in a "good" position (thus the mention "for a hadron collider").
     
  17. Aug 12, 2016 #16

    mfb

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    Some things have been studied with more precision at LEP, some things are studied with more precision at the B- and C-factories (low-energetic electron/positron colliders), some things are studied more precisely at the LHC. Every type of collider can do something better than all others.

    Typically the low-energetic experiments (B- and C-factories) are limited in the types of particles they can study (simply because they cannot produce more high-energetic particles), have a reasonable statistic and low systematic uncertainties.
    High-energy electron/positron colliders like LEP and the planned ILC or the Chinese collider can produce more different particles, but they usually have smaller samples, their systematic uncertainties are quite small as well.
    Proton-proton colliders like Tevatron and LHC can produce all known particles, they have huge samples, but they can have larger systematic uncertainties, and some processes cannot be studied with them at all because a full final state reconstruction is not possible.
     
  18. Aug 12, 2016 #17

    ChrisVer

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    Well, as far as B-factories are concerned, LHCb has become quiet the competitor for Belle experiment [even surpassing the predictions]. Indeed the precision is lower there, but the high luminosity [sample size] allows LHCb to make studies that people didn't expect it to achieve. Some studies are affected by this, some others are not (and should be done in experiments like Belle-2). It's a question of whether you have anything to gain by just achieving higher precision or not.
     
  19. Aug 12, 2016 #18

    vanhees71

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    Last but not least, one should not forget that there's also a heavy-ion program at the LHC! There's a lot to learn about strongly interacting hot net-baryon free matter that we don't know at high precision. So, even if the HEP endeavor does not result in "new physics" or "physics beyond the standard model", there's a lot more potential to go for high-precision experiments (of course the electromagnetic probes are very close to my heart, and I hope there will be a dilepton measurement at (least at) the accuracy level as the dimuon measurement by NA60 at the SPS!). For a review, see

    http://arxiv.org/abs/0901.3289

    Also on the HEP side, I'm not as frustated as Sabine. Particularly, I'd not call the confirmation of the Higgs particle "the LHC night-mare scenario" but great success, and indeed there's still a lot to measure and to learn even within the realm of the standard model. So the LHC doesn't end up empty-handed anyway even with the results it has produced now. Of course, it's a bit hard to sell to the taxpaying public and the funding agencies distributing the research budget.
     
  20. Aug 12, 2016 #19

    ChrisVer

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    :biggrin: afterall even analyses that look for those new physics start with 'denying' it....
     
  21. Aug 12, 2016 #20

    Dale

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    Closed pending moderation

    Edit: a thread hijack has been removed and the thread is reopened
     
    Last edited: Aug 12, 2016
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